The present invention relates to a switch device for selectively operating a plurality of switch elements provided in a case by depressing an operating knob rockably mounted on the case, and more particularly to a water proof structure of the switch device.
Such a switch device is used as a mirror switch for remote-controlling a mirror mounted on a body of an automobile, for example, from a driver's seat by a driving force of motors.
FIGS. 9 and 10 are a vertical sectional view and an exploded perspective view of a conventional switch device to be used as the mirror switch.
Referring to FIGS. 9 and 10, reference numerals 1 and 2 designate a case opened at its lower end and a cover for closing the open lower end of the case, respectively. The case 1 and the cover 2 are connected with each other in a snap fashion to form an outer shell of the switch device. A printed circuit board 3 is mounted on the cover 2, and four lever switches 4, a single slide switch 5 and connectors 15 are soldered to the printed circuit board 3. Each lever switch 4 is provided with an L-shaped actuator 4a projecting from an upper end thereof and with a lever 4b adapted to be rotated by depressing the actuator 4a to effect a switching operation. The slide switch 5 is provided with an operating lever 5a projecting from an upper end thereof and adapted to be slid to effect a switching operation.
The case 1 is formed on its upper surface with a recess 6 having a square shape in plan and a recess 7 having a track shape in plan, both recesses 6 and 7 being juxtaposed in plan. Four through-holes 8 are formed at four corners of the recess 6 in correspondence with the lever switches 4, and an upwardly projecting wall 10 having an opening 9 is formed at a central portion of the recess 6. The recess 7 is formed at its bottom with an elongated hole 11.
Reference numeral 12 designates an pusher knob having a square shape in plan. The pusher knob 12 is formed at its lower four corners with elongated vertical legs 12a projecting downwardly. Further, four short legs 12b are so formed as to project downwardly from the pusher knob 12 in such a manner that each leg 12b is located intermediate of the adjacent vertical legs 12a. The pusher knob 12 is further formed with pawls 12c depending therefrom. Four click rubber members 13 each having a conical shape shape are disposed between the bottom surface of the recess 6 and the four short legs 12b. Thus, the pusher knob 12 is received in the recess 6 in such a manner that the pawls 12c are engaged with a lower peripheral edge of the upwardly projecting wall 10. Accordingly, when the pusher knob 12 is depressed at its corner against an elastic force of the click rubber members 13, the elongated vertical leg 12a at the corner of the pusher knob 12 is lowered in the through-hole 8 to urge the actuator 4a of the corresponding lever switch 4 and thereby turn on the lever switch 4.
Reference numeral 14 designates a slider knob having an operating rod 14a depending therefrom. The operating rod 14a is inserted through the elongated hole 11, and is engaged with the operating lever 5a of the slide switch 5. Accordingly, when the slider knob 14 is moved along the recess 7, the operating lever 5a correspondingly reciprocated to conduct the switching operation of the slide switch 5.
The operation of the above prior art switch device is as follows:
When the slider knob 14 is reciprocated along the elongated hole 11, the slide switch 5 is operated to select a neutral position and a drive ready position for driving either of a right or left mirror. In the drive ready position, when the pusher knob 12 is depressed at its corner to be rocked in a given direction, the elongated vertical leg 12a at the depressed position of the pusher knob 12 is lowered to urge the actuator 4a of the corresponding lever switch 4 and thereby turn on the lever switch 4. In this operation, the click rubber members 13 are deformed by the depression of the pusher knob 12 to enable an operator to recognize the on-operation of the lever switch 4 with a click feeling. When the depression force applied to the pusher knob 12 is removed, the pusher knob 12 is returned to the position shown in FIG. 9 by the elastic force of the click rubber members 13. Thus, one of the four lever switches 4 is selectively turned on by selecting a position of depression of the pusher knob 12. As a result, a motor (not shown) is driven, and a driving force of the motor is transmitted through a power transmitting system (not shown) to the mirror selected by the slider knob 14, thereby driving (inclining) the mirror in a direction corresponding to the direction of depression of the pusher knob 12.
In the above-mentioned switch device, the elongated vertical legs 12a of the pusher knob 12 are vertically moved in the through-holes 8 of the recess 6 of the case 1 to selectively operate the switch element (the lever switch 4). As the pusher knob 12 is rocked, one of the elongated vertical legs 12a is moved horizontally as well as vertically. Accordingly, it is necessary to define a considerable clearance between each leg 12a and each through-hole 8, so as to permit such horizontal movement of the leg 12a. In the case that the switch device is exposed to a liquid such as rainwater and drinking water, there is a possibility that the liquid will enter the case 1 from a gap between the case 1 and the pusher knob 12 through the clearance of the through-holes 8, causing short-circuit of wiring patterns on the printed circuit board 3 and contacts of the switch elements 4 and 5. Although such short-circuit is hardly generated when the switch device is mounted on an instrument panel, the possibility of the short-circuit is remarkable when the switch device is mounted on the inside surface of a door of the automobile.